Method of making large area conformable shape structures for detector/sensor applications using glass drawing technique and postprocessing

ABSTRACT

A method of making a large area conformable shape structure comprises drawing a plurality of tubes to form a plurality of drawn tubes, and cutting the plurality of drawn tubes into cut drawn tubes of a predetermined shape. The cut drawn tubes have a first end and a second end along the longitudinal direction of the cut drawn tubes. The method further comprises conforming the first end of the cut drawn tubes into a predetermined curve to form the large area conformable shape structure, wherein the cut drawn tubes contain a material.

The present application is a divisional of U.S. patent application Ser.No. 12/558,101, filed Sep. 11, 2009, the entirety of which isincorporated herein by reference.

The present disclosure is related to U.S. patent application Ser. No.12/558,129 to Ivanov et al., filed Sep. 11, 2009, entitled “Method ForMorphological Control And Encapsulation Of Materials For Electronics AndEnergy Applications” and commonly owned by the assignee of the presentdisclosure, the entirety of which is hereby incorporated by reference.The present disclosure is also related to U.S. patent application Ser.No. 12/558,145 to Ivanov et al., filed Sep. 11, 2009, entitled “DesignOf Large Area Substrate For Surface Enhanced Raman Spectroscopy (SERS)Using Glass-Drawing Technique” and commonly owned by the assignee of thepresent disclosure, the entirety of which is hereby incorporated byreference.

This invention was made with government support awarded by the U.S.Department of Energy (Prime Contract No. DE-AC05-00OR22725). Thegovernment has certain rights in the invention.

TECHNICAL FIELD

The present disclosure relates to a method of making large areaconformable shape structures for detector/sensor applications using aglass drawing technique and postprocessing.

BACKGROUND

A focal plane array is an array of light-sensing pixels at the focalplane of a lens. Focal plane arrays are commonly used for both imagingand non-imaging purposes, such as spectrometry, and civil and militarysensing. Focal plane arrays operate by detecting photons at particularwavelengths and then generating an electrical charge, voltage, orresistance in relation to the number of photons detected at each pixel.This charge, voltage, or resistance is then measured, digitized, andused to construct an image of the object, scene, or phenomenon thatemitted the photons.

Typically, focal plane arrays are two-dimensional devices that aresensitive in the infrared spectrum. Focal plane arrays can operate atother spectra, such as the visible spectrum. Examples of focal planearrays sensitive in the visible spectrum include CCDs and CMOS imagesensors.

As the size of devices using focal plane arrays decreases, focal planearrays become smaller and more complex. A solution to reduce focal planearray complexity is to use curved focal plane arrays as opposed toplanar focal plane arrays. One advantage of a curved focal plane arrayis its field curvature. Curved focal plane arrays previously reportedhave a radius of curvature ≧5 meters.

BRIEF SUMMARY

In one aspect, a method of making a large area conformable shapestructure comprises drawing a plurality of tubes to form a plurality ofdrawn tubes, and cutting the plurality of drawn tubes into cut drawntubes of a predetermined shape. The cut drawn tubes have a first end anda second end along the longitudinal direction of the cut drawn tubes.The method further comprises conforming the first end of the cut drawntubes into a predetermined curve to form the large area conformableshape structure, wherein the cut drawn tubes contain a material. Inanother aspect, a large area curved shape structure comprises aplurality of bundled tubes having a first end and a second end along thelongitudinal direction of the bundled tubes. A detector material isdisposed inside of the bundled tubes. The detector material issubstantially continuous between the first end and the second end. Thefirst end is a curved surface with a radius of curvature, relative tothe longitudinal direction of the plurality of bundled tubes, of no morethan about 1 cm. Electrical circuitry is disposed on the second end.

In yet another aspect, a large area curved shape structure comprises aplurality of bundled tubes having a first end and a second end along thelongitudinal direction of the bundled tubes. A detector material isdisposed inside of the bundled tubes. The detector material issubstantially continuous between the first end and the second end. Thefirst end is a curved surface with a field view, relative to thelongitudinal direction of the plurality of bundled tubes, of about 90degree. Electrical circuitry is disposed on the second end.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a not-to-scale schematic view of the method of making largearea conformable detectors.

FIG. 2 is a not-to-scale schematic view of a conformable shape structurefor detectors with a curvature of about 1 mm and a field view of about180 degree.

FIG. 3 is a schematic oblique view of a portion of a bundle of compositerods.

FIG. 4 is a schematic oblique view of the bundle of composite rods shownin FIG. 3 after re-bundling and fusing.

FIG. 5 is a not-to-scale schematic illustration of an optical component.

FIG. 6 is a not-to-scale schematic illustration of a metal nanoparticleattached to a single protrusive phase.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present disclosure is directed to a method of making large areaconformable shape structures for detector/sensor applications using aglass drawing technique and postprocessing. It is provided a method ofmaking hemispherical curved focal plane array detectors, which can beused for imaging in the VIS-NIR-SWIR (about 400-1900 nm) spectralregion. It is also provided a conformable focal plane array forintegrating on a hemispherical surface, suitable for high-performanceimagers with a small form factor and with a wide field of view. Thepresent disclosure is also directed to detectors using the novelconformable curved focal plane arrays.

Large Area Conformable Shape Structures

According to one embodiment of the present disclosure, a method isprovided for making and shaping a large area conformable shape structurefor detectors based on a combination of a glass drawing technique andthermal post processing of assemblies obtained from the glass drawingprocess. Referring to FIG. 1A-1C, a bundle of tubes 1 is formed from aplurality of single dielectric tubes, such as glass tubes. The bundle ofglass tubes 1 is drawn, and redrawn if needed, to form a plurality ofdrawn glass nanotubes 2. The drawn glass nanotubes 2 are cut and shapedto form a conformable shape structure (conformable curved focal planearrays) 4. The cut drawn glass nanotubes can have any shape, such asplates, tiles, or disks. In one example, the drawn glass nanotubes 2 arecut into disks 3. Herein, the terms “conformable shape structures” and“conformable curved focal plane arrays” are used interchangeably. Thebundling, drawing, cutting, and shaping processes will be described indetail below.

Any suitable dielectric tubes can be used to prepare the conformableshape structure 4. For example, the dielectric tubes can be hollow glasstubes, or composite glass rods comprising a matrix material of the rodsand a core disposed inside of the matrix material. The core comprises adetector material. The drawn glass nanotubes 2 can assume any shape,such as a circle, a square, a rectangle, an oval, a triangle, ahexagonal shape, or an irregular shape. The cut drawn glass nanotubescan assume any shape in the transverse direction of the nanotubes, suchas a circle, a square, a rectangle, an oval, a triangle, a hexagonalshape, or an irregular shape. The cut drawn glass nanotubes can assumeany shape in the longitudinal direction of the nanotubes. Preferably,the cut drawn glass nanotubes have a disk shape in the longitudinaldirection. The thickness of the cut drawn glass nanotubes in thelongitudinal direction varies. In one example, the thickness is about0.1-10 mm.

The drawn glass nanotubes 2 function as dielectric-detector composites.The nanotubes electrically isolate individual detector material, whichis disposed inside of the drawn nanotubes. Each of the drawn glassnanotubes 2 with the isolated individual detector material forms a fiberfor the detector. Each fiber acts as a single imaging device (pixel).The size of the imaging device is defined by the number of pixels. Thesize of the individual pixel is determined by the drawing ratio, and canbe reduced down to submicron size (e.g., less than about 1 micron).Preferably, the size of the pixels is in the nanometer range (e.g. lessthan about 100 nm).

Electrical contacts (circuitry) are disposed at the individual pixels atthe respective ends distal to the field. The electrical contacts can beattached to the individual pixels before or after the shape-conformingprocedure. The detector material can be placed inside the insulatingtubes before or after the drawing/shape-conforming procedure via anysuitable method, such as infiltration, back-filling or synthesis. Forexample, the detector material is placed inside the insulating tubesafter the drawing/shape-conforming procedure by backinfiltration/filling. In one example, infiltration involves passing asuspension of a detector material through the tubes, and then allowingthe solvent in the suspension to evaporate and the detector material todeposit on the walls of the tubes. In another example, a chemicalreaction carried inside the tubes could be used to generate a sensorymaterial. In yet another example, back filling occurs when part of thetube is filled with a metal wire (electrode enabling electrical contactto a detector material) and then a detector material is deposited viaelectrochemical deposition (or other technique). After deposition of atransparent conductive top electrode (for example, indium tin oxide or ananotube network), a multi-pixel detector can be activated.

The shape structures according to one embodiment of the presentdisclosure are conformable. The nanotubes are drawn and shaped to becurved to various curvatures. Any suitable shaping method can be used.In one example, the nanotubes are shaped by heating and negative shapemodel. In one example, a nanotube suspension is sprayed on the surfaceof the nanotubes, and after solvent evaporation, the nanotubes conformto the surface. In another example, negative shape model provides asurface structure to which a detector can be conformed. For example, aslice of a multi-fiber (multi-pixel) is heated up to a softeningtemperature of the glass. Then a preheated slice of multi-fiber assemblyis pressed against a negative form and allowed to cool. After cooling,the shape of the detector is fixed. In yet another example, theconformable nanotubes are conformed into a curved shape either byattaching the conformable nanotubes to a rigid, curved substrate or byapplying a force through air pressure, a balloon, vacuum, orpiezoelectric tranducer (PZT) to conform the conformable nanotubes to aspecific curvature.

In one embodiment, the conformable shape structures are curved with aradius of curvature of about 1 cm or less. The curved shape structurescan have millions of pixels and a field view of about 90 degree or more.Preferably, the conformable curved shape structures have a radius ofcurvature of about 1 mm or less. Preferably, the field view is about 120degree or more. More preferably, the field of view is about 180 degreeor more. In one example, a conformable shape structure is conformed toand integrated on a hemispherical surface with a field of view of morethan about 180 degree. In another example, the field of view is about270 degree. In yet another example, the field of view is about 360degree.

Referring to FIG. 2, it is shown one design of a conformable shapestructure for imaging. The design is capable of a resolution of about1,000,000 pixels×infinite size for a cylindrical shape, a field view ofabout 180 degree, and a curvature of about 1 mm. The size of a singlepixel is defined by the outer diameter of a nanotube. In one example,the size of the pixel is about 300 nm. The active area of the singlepixel is defined by the inner diameter of the nanotube. In one example,the active area of the single pixel is about 100 nm. The wall thicknessof the nanotube is about 100 nm. The conformable shape structure 7,shown in dark shade, has about 1,000,000 pixel resolution in thetransverse direction and virtually unlimited pixel-resolution in thelongitudinal direction of the cylindrical shape.

The conformable curved shape structure can be connected, via theelectrical contacts at the individual pixels, to the remaining parts ofa detector system for spatially resolved detection of light (visible andUV as well as infrared) and low energy particles. Detection spectrum ofthe detector is determined by the detector material used.

Any suitable material can be used for the individual detector material.The material of the detector can be inorganic or organic, crystalline oramorphous. In one example, the inorganic materials can be amorphousinorganic materials that can be deposited and patterned on ahemispherical surface, or alternately, inorganic structures prepared ona planar substrate and then transferred to a non-planar surface. Theorganic material can be of a composite material to enable desiredsensitivity in particular frequency range. Examples of inorganicdetector material which could be drawn include, but are not limited to,Si (detection in about 180 nm to about 1100 nm), indium antimonide(InSb, detection in about 10,000 to 2,000 cm⁻¹ range),mercury-cadmium-telluride (HgCdTe), indium gallium arsenide (InGaAs),and vanadium oxide (VO_(x)). A variety of lead salts can also be used.One example is PbSe.

Preferably, the thermal properties of the inorganic detector materialmatch the softening point of the dielectric material in the nanotubes(such as glass). The detector material can then be drawn and shapedalong with the dielectric material or back-infiltrated with or withoutvacuum aid afterwards. For example, the thermal properties of InSb shownin Table 1 below indicate that the material melts at about 527° C.,which is close to the softening temperature of some glasses. Thus, theInSb material can be co-drawn with glass. The data in Table 1 areadapted from Gold bery Yu. A., Handbook Series on SemiconductorParameters, M. Levinshtein, S. Rumyantsev and M. Shur, ed., WorldScientific, London, 1996, the entirety of which is hereby incorporatedby reference. Also, in order to select the appropriate glass material,the glass thermal expansion coefficient (TEC) needs to be consideredsuch that during the cooling step, stresses will not develop at theinterface of glass and the InSb material.

TABLE 1 Thermal Properties Of InSb Bulk modulus 4.7 × 10¹¹ dyn cm⁻¹Melting point 527° C. Specific heat 0.2 J g⁻¹ ° C.⁻¹ Thermalconductivity 0.18 W cm⁻¹ ° C.⁻¹ Thermal diffusivity 0.16 cm² s⁻¹ Thermalexpansion, linear 5.37 × 10⁻⁶ ° C.⁻¹

Any suitable method can be used to deposit the detector material insidethe drawn nanotubes (pixels). For example, when an inorganic material,such as InSb, is used as the detector material, the detector materialcan be deposited by any suitable growth methods for InSb, such assolidifying a melt from the liquid state, epitaxially by liquid phaseepitaxy, hot wall epitaxy or molecular beam epitaxy, or from theorganometallic compounds by MOVPE (metalorganic vapor phase epitaxy).

The large area conformable shape structures according to embodiments ofthe present disclosure may be compact and inexpensive. The processingmethods are easily scalable to enable light-weight detection systems.The focal plane arrays can be incorporated on a hemispherical surfacefor high-performance imaging systems with a small form factor and widefield of view. Such systems are expected to surpass the performance ofplanar focal imaging arrays. The flexibility of the method enablesconformable shape structures of various curvatures, as small as orsmaller than about 1 cm, to be produced. The number of pixels iscontrolled by the tube diameter, which can be in the nanometer size. Thedetectors may have a field of view greater than 90°.

Novel detectors according to embodiments of the present disclosure mayallow the use of fewer optical elements and eliminate the need for imagepost processing since the hemispherical planar array can inherentlycorrect for spherical, field curvature, and other optical aberrations.The detectors perform over a wide 400-1900 nm spectral band on curvedsurfaces. The detectors have a field of view of greater than 90°, whichallows for a simple optical design, and thus may reduce the weight ofthe overall system. The improved functionality can be beneficial to avariety of applications, such as many military applications, by reducingor eliminating the need for multiple detectors or gimbals, and thuslessening the mechanical and optical complexity of the system normallyrequired to achieve a wide field of view.

The improved functionality is very beneficial to various civil andmilitary applications which may benefit from decreased complexity ofmechanical and optical detection and access to a wide field of view.

Glass Drawing Techniques

The nanotubes can be prepared by any suitable method, for example, byetching, chemical or physical vapor deposition, laser vaporization,electrical field manipulation, hydrodynamic flow, lithographictechniques, synthetic methods, and glass drawing techniques. Preferably,the nanotubes are prepared by glass drawing techniques.

In one embodiment, composite glass rods are drawn. Referring to FIG. 3,composite rods comprise a core 14 and a sleeve (the matrix material ofthe rods) 12. The core 14 comprises a different material than the matrixmaterial 12. The composite rods are bundled in an aligned array, orbundle 10. The rod (matrix material) 12 and the core 14 can assume anyshape. Preferably, the rod (matrix material) 12 has a hexagonal or otherouter cross-sectional shape to minimize voids while the core 14preferably has a circular cross-section, although neither of theseparameters is considered to be critical. It may be advantageous foreconomical manufacturing for the matrix material 12 to have a circularcross-section. In this case the voids are filled in during subsequentprocessing. With round rods 12, the spacing of the core 14 will besomewhat less precise.

The matrix material 12 and core 14 are preferably selected based ondifferential etchability (susceptibility to etching or dissolution). Inthe case of the nano-channel glass drawing, the core glass has a muchhigher etchability than that of the matrix glass. Alternatively, if thecore 14 has a lower etchability than the matrix material 12, protrusive,sharp features, such as nanocones and nanospikes, may form upon etchingof the composite surface if the etch contrast is low. If the etchcontrast is high, the protrusive features will be cylindrical.

It should be noted that the use of immiscible components in thecomposite may improve the ease of drawing the material. In general itmay be advantageous to choose materials with specific miscibility tofacilitate drawing without too much inter-diffusion of the materials(excessively miscible) and without either component breaking up intodroplets (insufficiently miscible).

The bundle 10 can heated to a temperature sufficient to soften thematerials comprising the bundle 10, but low enough to avoid damage,decomposition, or other deleterious changes. The bundle 10 is thendrawn, under vacuum, along the axis of the bundled rods to fuse andreduce the diameter of the bundle 10. The drawn bundle has reduced sizematerial rod matrix material 12 and respective core 14. The drawn bundleis cut transversely into sections which can be re-bundled to increasethe number of core material cores in the cross-section thereof.

The drawn bundle can then be cut into segments, re-bundled, and drawnagain. The twice-drawn bundle has further reduced size material rodmatrix material 12 and respective core 14. The twice-drawn bundle isagain cut transversely into sections which are re-bundled to furtherincrease the number of core 14 cores in the cross-section thereof.

The process of bundling, drawing, and cutting can be performed a singletime or repeated many times until the desired diameter and spacing ofthe core 14 are obtained. Core 14 diameters and spacing on the nanometerscale are possible. The sizes of bundles and the number of rodscontained therein can be varied throughout the process as desired.

After the final draw (which can be the first draw), the bundle can becut, bundled, and fused in order to obtain a larger diameter boule.Referring to FIG. 4, the boule 40 can be transversely cut to produceslices (plates, tiles) of any desired thickness. The cut is usually (butnot necessarily) perpendicular to the original rods 12 and the drawingdirection. One or both cut faces may be polished. Although a hexagonalboule 40 is shown and described as an example, a boule of any desiredgeometric shape can be formed, processed, and used.

In another embodiment, the composite material may comprise a bundle ofmore than one kind of composite rod, as described in U.S. PatentPublication No. 2006/0289380, the entirety of which is herebyincorporated by reference. For example, some of the cores may have adifferent core phase having a high etchability/solubility (e.g.,nano-channel-like cores) so that a perforated product may be fabricated.

In yet another embodiment, solid glass rods or hollow glass tubes areused as opposed to composite glass rods. The process of bundling,drawing, and cutting is otherwise performed as described above.

In further another embodiment, glass tubes that contain appropriatefilling materials in powder or rod form are drawn. The drawing methodaccording to the embodiment combines fiber drawing method with advancedfilling materials, thus providing not only desired functionality, butalso excellent controls over the aspect ratio, diameter, length andinter-nanotube spacing of micro/nanotubes.

A preform for drawing may be prepared by pouring powders or inserting arod into a glass tube. Drawn tubes from the first drawing process arecut into pieces, preferably with substantially equal length, which arebundled together to form a hexagonal bundle for the next drawing cycle.By repeating the drawing-cutting-bundling process for as many, or asfew, times as needed, the outer and the inner diameters, and thethickness of the glass tubes may be decreased from centimeters tohundreds nanometers or less.

After the last drawing, the drawn nanotubes are bundled and annealedbelow the softening temperature of the glass to make a solid rod. In oneexample, the rod is cut perpendicular to its axis to make plates thathave ordered array of micro/nanotubes of the filling materials. Ifneeded, after making encapsulated nanotubes, the glass can be removed byetching, such as hydrogen fluoride etching. The nanotubes prepared canhave a nanometer size diameter, and a length of several meters orlonger. Preferably, a vacuum pump is connected to the glass tube, andthe drawing is done in vacuum to avoid the possible oxidation of thefilling materials and to make an intimate contact between the glass andthe filling materials.

Any suitable material can be used as the filling material in thepreform. Preferably, the softening temperature of the glass is betweenthe melting temperature and the boiling temperatures of the fillingmaterial. Preferably, the coefficients of thermal expansion of the glassand the filling material at the drawing temperature are close to eachother, or the filling material is in liquid. Preferably, there issubstantially no chemical reaction between the glass and the material atthe drawing temperature. Preferably, the molten material has certainwettability to the glass surface. Preferably, the materials do not havehigh vapor pressure at high temperature.

The drawn nanotubes can be etched and/or coated using any suitablemethods. For example, the drawn nanotubes can be etched and coated asdescribed in U.S. Patent Publication No. 2006/0289380, the entirety ofwhich is hereby incorporated by reference.

Structured Nanomaterial

The glass drawing technique can be used to prepare structurednanomaterials. The structured material can assume various periodicitiesand shapes. For example, the structured nanomaterial can be comprised ofnanotubes with protrusive features such as spikes and cones, hollownanotubes, or filled nanotubes. The structured nanomaterial can besuperhydophobic or superhydrophilic. The periodicity of the structurednanomaterial can be determined by the periodicity of the bundled tubesbefore drawing.

In one embodiment, nanotubes with protrusive spikes are used to preparea structured nanomaterial. Referring to FIG. 5, protrusive phase 18 is asolid material, also referred to as detector material. Each of theprotrusive phases 18 is used as an optical waveguide, also referred toas an optical conduit, a pixel, or a fiber for the purposes of thepresent disclosure. The optical conduits are generally, but notnecessarily, cylindrical in shape between the proximal and distal endsof the optical component. Light of a selected wavelength or range ofwavelengths (e.g. infrared, visible, and/or ultraviolet light) may betransmitted through an optical conduit of the protrusive phasedielectric material 18. The differentially etched, composite, orderedmaterial having sharp surface features can thus be used as an array ofoptical waveguides having sharp pointed tips.

In one embodiment, for practical optical components, an optical conduitis realized by having the refractive index (nf) of the core materialcomprising the protrusive phase that exceeds the nf of the recessivephase, which functions as the cladding, by at least about 0.1 percent ata selected wavelength or wavelength range. The greater the difference ofnf, the more the light intensity is concentrated to the core region. Toosmall an index difference leads to the spatial energy spreadsignificantly protruding into the cladding phase. For example, a corephase having an nf of about 1.46 can have a cladding with an nf of about1.45, and generally act as a good waveguide. An array can have a commonrecessive material but different protrusive materials for individualoptical conduits such that individual optical conduits can havedifferent optical properties.

Referring to FIG. 5 again, an optical component 24 has a distal end 22that comprises an array of optical waveguides having sharp surfacefeature tips or spikes 18. Such an array can have from as few as two tomore than one billion per square centimeter of individual, parallel,optical waveguides having sharp points that can be used as massivelyparallel sensors, parallel scanning optical microscopy probes, and thelike. The optical waveguides comprising the optical component 24 can beoptical conduits of any desired length and diameter, a plate or wafer ofany desired thickness and diameter, or any other desired size and shape.The optical waveguides comprising the optical component 24 can beflexible or rigid, elastic or inelastic. The individual strands ofprotrusive phase that form the discrete tips or spikes 18 and theirassociated optical conduits run substantially parallel to one anotherand completely (continuously) through the optical component 22 and arethus individually addressable as discrete areas 26 at a proximal end 28.In a typical arrangement, the optical waveguides are optical conduitscomprising the protrusive phase having circular cross-sectionssurrounded by the ambient (e.g. air which provides the requiredsurrounding other dielectric material with a lower refractive index)adjacent to the tips or spikes 18. The protrusive phase is generallysurrounded by the recessive phase in regions other than those adjacentto the tips or spikes 18. To achieve individual addressability fromdiscrete areas 26 at a proximal end 28, in a typical embodiment therecessive phase is a dielectric material having a lower refractive indexcompared to the protrusive phase material.

It can be understood from the description hereinabove that at least theprotrusive phase must be sufficiently optically transparent at theselected wavelength(s) to be characterized as an optical waveguide. Theoptical waveguide can be a material wherein the attenuation length oflight of the selected wavelength(s) is at least as long as the averagelength of the sharp surface features of the protrusive phase. It ispreferable that the attenuation length of light of selectedwavelength(s) be at least ten times as long as the average length of thesharp surface features of the protrusive phase.

The selected wavelengths of light are guided (confined) through theprotrusive phase. In one embodiment, the mechanism for guiding lightthrough the optical conduit is for the protrusive phase to becharacterized by a higher index of refraction than the recessive phasefor at least one selected wavelength, a selected range of wavelengths,or a group of selected wavelengths of light. The protrusive phase thusacts as a waveguide for the selected wavelength(s) of light. In anotherembodiment, the recessive phase can be reflective or a reflectiveinterface material can be present between the recessive and protrusivematerials, such that light at the selected wavelengths is reflected,thus confining the selected wavelengths of light to the protrusivephase. For example, the recessive phase or the interface material can bea metal or metal alloy.

The reflection that occurs at the interface of the recessive andprotrusive phase materials can be enhanced by the formation of ametallic “mirror” film at the interface. Various methods can be employedto generate this film. One method comprises drawing recessive glasstubes into which soft metal, such as gold, or a metal composite, such asgold or gold-silver composite, coated protrusive glass rods have beenplaced. The soft (low melting point) metal will tend to melt as theglasses soften. As the glasses get drawn, the molten metal conforms tothe interface between the narrowing tube and rod. The recessive glasstubes also coalesce into the support structure. As the glasses cool andharden so will the metal forming the mirror surface around the narrowedprotrusive rod. Combined with bundling, fusing, wafer cutting, andetching, as described above, metal mirrored arrays can thus be formed.

Another method of forming a metal mirrored protruding phase involvesusing a high temperature melting metal (such as platinum and tungsten)coated glass rod to form the arrays. These metal coated glass rods canbe inserted through the core of recessive glass tubes. The recessiveglass tubes can then be drawn such that the respective tube coalescesaround the metal coated rod without the metal melting or softening asthe tube is drawn. Subsequent cutting, bundling, and fusing, asdescribed above, can be used to create a metal mirrored array.

The metal can then be etched along with the recessive and protrusiveglasses. Depending on the relative rates of etching, various recessed orprotruding metal features can result. By proper choice of the etchant ormixture of etchants a desired structure can be formed at the distal endof the optical component. By use of a metal or other reflective materialat the interface of the protrusive phase optical conduit and therecessive phase support structure, the protrusive phase can have arefractive index that is greater than, equal to, or less than therecessive phase yet perform the required waveguide function.

For some applications, it may be desirable to produce the opticalconduits in the form of a long column with the protrusive surfacefeatures at the distal end of the column to transmit the selectedwavelengths of light over a distance through the protrusive phase.Moreover, it may be desirable to produce tapered conduits with the sharpsurface features protruding from the tapered distal end of the conduitwhile a larger cross section proximal end of the conduit is more easilyand individually addressed. Such tapering conduits are particularly easyto produce if the material is produced by drawing and bundling glassfibers as described above.

The optical waveguides can be used in at least two basic modes. In onemode of operation, light guided through the protrusive phase from theproximal end propagates to the sharp, protrusive features at the distalend, interacts with an analytical sample, and returns back through theprotrusive phase to the proximal end as an optical data signal to areceiver or array of receivers contacted at the proximal end. In anothermode of operation, light directed onto an analytical sample via anothermeans interacts with the sample, is picked up by the sharp protrusivefeatures at the distal end, and is guided through the protrusive phaseto a receiver or array of receivers connected to the proximal end.

The optical waveguides can be utilized in various optical instrumentsthat operate in one or both of the above described modes. Potentialapplications include analytical processes where small regions of spaceneed to be optically probed, particularly in cases where it is desirableto probe many regions over an area simultaneously.

In one embodiment, the probe tips are functionalized to change theiroptical response as a result of biological or environmental contaminantsor other chemical constituents. For example, the optical waveguides canbe used as Surface Enhanced Raman Spectroscopy (SERS) probes. Referringto FIG. 6, a metal nanoparticle 31, such as a gold nanoparticle adheringto a single protruding feature 32 extending from the support structure33 at a distal end of an optical component, can be employed for a SERSprobe. Specifically, the distal (protrusive) end of the probes can bemodified with SERS active structured nanoparticles, so that the multiplenanoparticle containing probe tips can be used for SERS as amulti-tipped sensor or probe, with the option of spatially resolving thesignal. Using the evanescent optical fields of each protrusive feature,an array of protrusive features can be used instead of a single tip in aprobe, thus gathering many data points in parallel and accelerating theimage acquisition process. The protruding tips can be coated with a thinadhesive layer, for example a monolayer of ethyleneimine deposited fromsolution, and brought in contact with a surface decorated withnanoparticles of gold or some other metal, which adheres metalnanoparticles to the protrusive features.

As a fiber with sharp features on the end, the optical waveguides may beused as biological probes. In particular, an intracellular probeconnected to an optical microscope or spectroscope can be formed fromthe fiber with sharp features on an end.

In most configurations, instruments that use the optical component mayalso include other components used in optical instruments, as describedin U.S. Patent Publication No. 2008/0080816, the entirety of which ishereby incorporated by reference.

While the present disclosure has been described with reference tocertain embodiments, other features may be included without departingfrom the spirit and scope of the present invention. It is thereforeintended that the foregoing detailed description be regarded asillustrative rather than limiting, and that it be understood that it isthe following claims, including all equivalents, that are intended todefine the spirit and scope of this invention.

1. A method of making a large area conformable shape structure,comprising: drawing a plurality of tubes to form a plurality of drawntubes; cutting the plurality of drawn tubes into cut drawn tubes of apredetermined shape, the cut drawn tubes having a first end and a secondend along the longitudinal direction of the cut drawn tubes; andconforming the first end of the cut drawn tubes into a predeterminedcurve to form the large area conformable shape structure, wherein thecut drawn tubes contain a material.
 2. The method of claim 1, whereinthe material is substantially continuous along the length of the cutdrawn tubes.
 3. The method of claim 1, wherein the material is disposedinside of the tubes before drawing.
 4. The method of claim 1, whereinthe material is disposed inside of the cut drawn tubes after conforming.5. The method of claim 1, wherein the material is disposed via a methodselected from the group consisting of infiltration, back-filling,synthesis, and combinations thereof.
 6. The method of claim 1, whereinthe plurality of drawn tubes are cut transversely.
 7. The method ofclaim 6, wherein the predetermined shape is a disk.
 8. The method ofclaim 1, further comprising: bundling the plurality of tubes beforedrawing.
 9. The method of claim 8, wherein the bundling, drawing, andcutting steps are repeated at least once.
 10. The method of claim 1,wherein the respective cut drawn tube has a nanometer size diameter. 11.The method of claim 1, wherein the melting point of the material isclose to the softening temperature of the tubes.
 12. The method of claim1, wherein conforming the first end of the cut drawn tubes comprisesheating and negative shape modeling.
 13. The method of claim 1, furthercomprising: disposing electrical circuitry on the second end of the cutdrawn tubes.